David Cameron feels sorry for Ed Miliband “in his quieter moments” following particularly bruising exchanges in the House of Commons, Iain Duncan Smith has suggested.

The Work and Pensions Secretary said the Prime Minister had “sympathy in his quiet days for someone in the opposition” but he can’t show that publically.

Mr Duncan Smith who survived unscathed from Mr Cameron’s recent reshuffle despite wide speculation that he could lose his job after a conversation which appeared to refer to his future was overheard on a commuter train.

Politics, Mr Duncan Smith said, is “funny” and “quite bizarre and stupid” and warned that most of it was made up of people who had no other job than to gossip about other people.

In an interview over lunch with BBC radio said: "I find the whole business of politics funny, it's really quite bizarre and stupid.

“Just all this stuff running around briefing against each other and it doesn't actually change the price of bread. It's just people not being able to do anything else but gossip about other people.”

He added: "Somebody said the other day that the cabinet meeting now might as well be held in public because, frankly, at least some of the stuff we say might get out correctly rather than as it does, with everybody else briefing."